In the field of inking ribbons, a supply spool and a take-up spool have been provided on opposite sides of a typing or printing station with means for reversing the direction of travel of the ribbon to obtain longer ribbon life. The inking ribbon has usually been made to travel along a line of printing wherein the spools are positioned beyond the ends of the printing line, however in the case of certain printers, a wide ribbon is used and is made to travel in a direction normal to the print line.
In present day printers, it is common practice to use a ribbon cassette carrying an endless ribbon which is caused to be driven past the printing station with the ribbon being either a pre-inked ribbon or a ribbon which is to be continuously or frequently re-inked during the printing operation. The ribbon cassette may be of the stuffing box type, wherein the ribbon is contained within the cassette in random manner and the ribbon is unfolded at the cassette exit and is caused to be driven past the printing station and then trained to enter the cassette to be folded in random manner therein. A ribbon may be utilized in a mobius loop configuration wherein the ribbon is in substantially continuous contact with an inking core or the ribbon may have a plurality of coils around a core for controlled inking thereof.
Representative prior art in ribbon cassettes is shown and described in U.S. Pat. No. 2,755,905 issued to J. Segui on July 24, 1956, which shows an endless ribbon feeding device consisting of a flat case for attachment to the machine and having an inked pad means for rotating the inking pad in a step-by-step method and two return pulleys over which the ribbon passes and which forces the ribbon to surround the inking pad along with a spring for maintaining the tension of the ribbon constant during printing operations.
U.S. Pat. No. 3,887,056 issued to J. H. Lehmann, on June 3, 1975 discloses a demountable pluggable tensioning and re-inking cartridge which includes a plurality of inking rollers operable with a tension roller, the cartridge being removably attached with the frame of associated apparatus. An adjustable self-tensioning means holds the ribbon in a taut condition in a printing position and holds the ribbon in frictional contact with the re-inking members.
U.S. Pat. No. 3,904,017 issued to T. E. Frechette on Sept. 9, 1975 shows a ribbon cassette with a pre-threaded vibrator and ribbon feed means with the ribbon being placed in a stuffing condition in right and left housings.
U.S. Pat. No. 3,941,231 issued to G. C. Matuck et al. on Mar. 2, 1976 discloses a ribbon cartridge for an endless loop ink ribbon wherein the ribbon is in a cartridge which includes elongated guide members to confine the path of the loop of ribbon outside of the cartridge to a predetermined path and to allow for insertion of the cartridge into the machine without the necessity of threading the inked ribbon through fixed guides on the machine. The cartridge is of the stuffing box type, and includes drive rollers at one side of the cartridge and a friction block at the outlet of the cartridge.
U.S. Pat. No. 3,974,906 issued to S. L. Lee et al. on Aug. 17, 1976 shows an endless loop cartridge with random storage and wherein a pair of spaced guide means are used to provide for easy threading in a principal cavity of the cartridge and a secondary cavity prevents a loop of the ribbon from coming out of the cartridge in unsupported manner. A pair of drive rollers receive the ribbon for driving thereof into the principal cavity and a spring is positioned with a surface at the exit end of the cartridge for providing friction on the inked ribbon.
And, U.S. Pat. No. 3,989,132 issued to A. B. Carson on Nov. 2, 1976 shows ribbon storage and transport mechanism wherein a ribbon cartridge includes drive rollers for driving the ribbon into a stuffing box cavity and a plurality of restrictors at the exit end of the cavity prevent the ribbon from jamming at the exit port. One embodiment of the invention includes a single dam positioned to restrict the path of the ribbon and a second embodiment consists of two dams to restrain the ribbon at the exit port. Means are also provided for inputting the ribbon inside the cartridge and to extend the ribbon usefulness and life by presenting two ribbon edges to the print head.